Error during backup and restore script execution for Orion NX 16 GB on l4T ver 35.5 JP 5.1.3

In the dev kit there are using trans receiver( I am not sure, can you confirm !) (pull ups/pull downs etc ) within the dev kit board,
where as we are directly taking the uart tx/rx/ lines from SOM module( as per our hardware guy ) with our custom carrier board.

Might be this is causing the issue. Because as soon as we give power( using USB cable serial convertor connected to some host PC) to the external transreceiver connected to the UART debug console pins tx/rx/gnd, we see the issue stops.

Might be the voltage levels are floating on the tx/rx/ lines directly brought out from SOM module.
what is your opinion on this.

Thanks.